Birth control pills generally contain estrogen and progesterone. The principle of birth control pills to regulate menstruation is to adjust the level of estrogen and progesterone in the body by taking birth control pills, so that the original abnormal hormone levels can be adjusted to normal. The short-acting contraceptive pill is usually taken from the first day of menstruation for twenty-one consecutive days, through taking the short-acting contraceptive pill can make the ovarian secretion of sex hormone levels to regain a balance, in about a week after stopping the pill will come to menstruation, stop a week and then start taking the next cycle of drugs, so that the original irregular menstruation will slowly return to normal. This will bring the irregular menstruation back to normal, and you should also pay attention to regular life while regulating menstruation with medication.